XXIV 



■ — successful attempts at least — were made to precipitate the 

 copper held in solution by the adit water.* About 1854, how- 

 ever, a person who had gained some experience in the works of 

 Cuba, commenced operations on the stream. The success of his 

 experiments stimulated his neighbours ; and, in course of eight 

 or ten years, at least a dozen other parties had set themselves to 

 work on its bank, between the mouth of the Adit iiear Ferny- 

 splat t and the tide at Tarnon-dean, a distance of perhaps a mile 

 and a quarter. 



The quantity of water discharged by the adit, averages about 1,450 cubic 



feet (8,800 gallons) per minute ; I 

 „ saline matter |1 contained in it averages about 735 grains 



(1| ounce) per cubic foot ; § 

 ,, precipitate collected for some time past, has ranged from 



80 to 100, and averaged perhaps 90, tons a year. ^ 



The proportion of fine copper contained in the precipitate 

 varies from about 6^ to 61|, and averages nearly 40 per cent.* * 



thus 423 parts of precipitate) /are, on an average, extracted from 



containing. . 165 ,, fineco^jperj" \ 100,000,000 parts of water. 



in other words, 



3,784 cubic feet, or about 175 tons of water yield 1 lb. of precipitate p 

 or 9,693 „ „ 270 ,, 1 lb. of fine copper. 



The capacity of this fine Room ft is about 24,000 cubic feet; 

 a volume of the adit water of the same dimensions and average 

 richness would, therefore, yield less than two shillings worth of 

 metallic copper. 



Before the establishment of precij)itation-works, therefore, the 



* " In 1839 — 1840 the adit effected, in the mines it unwatered, a saving 

 of about £19,000 a year in fuel alone." 



Henwood, Cornivall Geol. Trans., v, p. 420. 



f Written Furnace-plat in the Ordnance Map, Sheet xxxi. 



+ Thomas, Cornvmll Geol. Trans., v, p. 422. Henwood, Ibid., p. 423. 



II Principally the salts of Sodium and Calcium. Fox, Cornwall Geol. 

 Trans., iii, pp. 323 — 4. Miller, Reports of the British Association for 1864, 

 Part ii, p. 36. 



§ Henwood, Cornivall Geol. Trans., viii, p. 586. 



^[ For this information I am indebted to the Idnduess of Mr. Henry 

 Williams, of Alma, near Truro. 



* * These assays have been obligingly communicated to me by Mr. Howard 

 Bankart, of the Red Jacket Copper Works, near Briton Ferry. 



f \ The Council-chamber of the Truro Corporation. 



